Electric meter



T. W. VARLEY.

ELECTRIC METER.

APPLICATION FILED nic. l2. 191s.

Patented Sept. 14, 1920.

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WITNESSES T. Wl VARLE'Y.

ELECTRIC METER.

APPLICATION FILED DEC. I2, 1918.

Patented Sept. 14, 1920.

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A TTOHNEIS UNITED STATES PATENT OFFICE.

THOMAS W. VARLEY, OF NEW-YORK, N. Y.

ELECTRIC METER.

Application filed December 12, 1918. Serial No. 266,436.

T0 all wiz/0m t may concern.'

Be it known that l, THOMAS lV. VARLEY, a citizen of the United lbtates, residing in the city, county, andtate of New York, have invented certain new and useful Improvements in Electric Meters, of which the following is aspeciiication. j

My invention relates to electric meters and is more particularly concerned with what are known as direct current watt-hour meters, or meters for the measurement of the' energy consumed by lamps, motors or other little liable to derangement, it will be'subject to exceedingly small frictiona'l losses, and its inertia will also be very small.

Still another object of my invention is to provide a meter of the class described in which the soft iron parts shall be substantially free from hysteresis errors. i

Yet another object of my invention is to provide a meter of the class described which shall give indications directly proportional to the product of E. M. F. and current without correctionof any kind.

My invention includes a special form of.

frictionless quick break commutating switch for reversing the current through the E. M. F. coils. 1

@ther objects of the invention. will appear as the specification proceeds.

My invention may be briefly described as comprisingone or more very light and small soft iron elements Fixed upon a rotatable shaft, cach element beingso related to two pairs of fixed coils that oppositely acting torques are simultaneously imposed upon the element. Each pair of iixed coils is identi* cal with the other pair and comprises a load coil (carrying current proportional to the load to be measured and an E. M. F.V

coil carrying current proportional to the E. M. F. of the load current). f The several coils are so connected up that the magneticflux produced by the two load coils has the same sign while that of the two E. M. F. coils is of opposite sign. Hence if a, represents the ampere turns (proportional to the magnetic-flux) for each load coil, and Z9 the ampere turnsof each E. M. F. coil, then since the torque is proportional to the magnetioflux squared, the net resultant torque tendingto turn the rotating member may be expressed as where K is a constant.

By periodically reversing the E. M. F. coils at appropriate times, continuous motion of the rotatable soft iron member will be produced and the speed of such motion at any instant will, of course, be proportional to the torque as above set out, it being understood, of course, that the usual magnetic brake or equivalent thereof, supplying load'proportional to the speed, is arranged to act upon the rotating system. rl`he total ofthe revolutions in a given time, readily determinable by gearing the rotatable member to a suitable integrating mechanism, will be .a measure of the total watts or energy developed during such time.

My invention will be better understood by referring to lthe accompanying drawings in which Figure l represents a front elevation of a preferred embodiment thereof, the casing of the meter being removed; Fig. 2 represents a view, part section, taken from the right of Fig. 1*, the casing being shown; Fig. 8 is adiagrammatic view showing the relation ofthe-operative parts and the wiring system; Fig. 4 is an enlarged aXial sec- Speecation of Letters Patent. Patgntd Spt.k 14, 1920 tion, part elevation, of the magnetic comn mutating switch; and Fig. 5 is a cross-section taken along the line 5-5 of Fig. 4.

In the drawings, a skeleton frame, l, of cast aluminum or other suitable material, supports four pairs or sets of coils 2, 3, 4, 5.

These coils are disposed in line one abovey the other in parallel planes, and are all set at an angle of 450 with the front of the meter.

Each pair or set of coils is identicalwith every other set, and comprises a load coil, G, and an E. M. F. or voltage coil, 7. The two coils are given the shape of short tubes and are cemented together and in yshallow aluminum cups,v 8,'fastened to supporting disks, 9, by screws, l2. The center portions of these cups are cut away so as to leave a narrow supporting flange, l'l, against weich the set of coils abuts. Disks, 9, are themselves attached to frame, 1, by screws, 10.

rllhe windings of the load and voltage coils are suitably determined according to the magnitude of the maximum load, of the E. M. F. and with reference to other considerations, as is well understood by those skilled in the art.

rllhe rotating system, member or element, 13, comprises a slender stein or spindle, 14, supported vertically, so as to intersect the axis of each pair of coils at the same relative point, in bearings, 15, and, 16, the former adjustably fastened directly in the top of frame, 1, a .d the latter at the bott-om supported as will later be described.

innig from the bottom supporting disk, il, is a pair of cylindrically bored pole pieces, 1?, to which is fastened a permanent magnet, 18. l disk or cap, 19, fastened to the bottom of the pole pieces, supports a cylindrical soft iron core, 20, conoentrically within the pole pieces, the core being provided at the bottom with a substantially centrally bored and threaded stem, 21, which is also threaded externally so as to be engaged by a clamp nut, 23, by means of which the core is clamped fast against the disk.

The previously referred to bottom bearing, 16, is at the top of a threaded plug, 22, which is fitted into the central bore of stern, 21. rThe core, 20, is bored out in line with this central plug.

an inverted and very thin walled aluminum cup, 24, occupies the narrow annular space between core, 20, and pole pieces, 17, and is carried by the spindle, 14, so that, as the spindle rotates, a drag or load proportional to the speed of rotation of the spindle will be imposed thereon. rllhis feature is well known in the art and does not form any part of the invention.

The top of spindle, 14, is provided with a worm, 25, meshing with a gear, 26, constituting part of an integrating system, 27, graduated in terms of kilowatt hours and fractions thereof, as is usual in the art.

Mounted upon a disk, 28, similar to the supporting` disks, 9, immediately above the top set of coils, 2, is a disk, 29, of hard rubber or equivalent material. Spaced 900 apart and fastened concentrically upon the disk are four pairs of contacts, 2, 3, 4a, 5a. Each pair of contacts consists of a pair of radially disposed lugs in which are, respectively, an outer inwardly faced contact, 30, and an inner outwardly faced contact, 31. These contacts are, preferably, adjustable radially.

Fastened to the underside of a disk, 32, some little distance above disk, 29, are insulating blocks, 33, one for each pair of contact-s, 2a, 3a, 4, and 5'. Fastened to each block is the upper end of a very light steel leaf spring 2b, 3b, 4b, and 5b. The leaf springs are supported at equal distances from the center of disk, 82, and so as to be capable of being swung in planos respectively coincident with the planes of the contact pairs 2"', 3a, 4, and 5a. The length and adjustment of the leaf springs is such that their lower ends, which are faced with platinum on each side, will normally rest between the members of each contact pair and against the outer member ofl each pair.

Fixed concentrically upon the spindle, 14, is a substantially quadrantal segment, 34, of magnetized hardened steel constitutinga permanent magnet. The radius of this segment is, preferably, just a trifle less than that of the inner members of each contact pair, 2a, 3a, 4a, and 5a.

\ As the spindle, 14, revolves, carrying with it the segment, 34, the leaf springs, 2b, 3b, 4b, and 5b, will be successively acted upon so as to be momentarily pulled away from the outer to the inner member ofthe contact pairs, falling back once more against the outer member as soon as the segment, 33, has passed.

The magnetic commutating switch, as described, is not only advantageous in that it is frictionless but in that it is, also, substantially non-arcing, it being easily possible to so adjust the leaf springs that their movements in correspondence with the rotation of the magnetic segment, 34, will be substantially instantaneous.

It is obvious that each leaf spring` will successively be attracted by the quadrantal segment before the preceding leaf spring is released and permitted to swing outwardly against the inwardly faced contacts, 30. The torques, due to the several pairs of coil sets, will, therefore, overlap somewhat.

In the embodiment of my invention `herein described and illustrated, the several dimensions kof the magnetic commutating switch have been so chosen that each pair of coil sets exerts its torque through approximately 110o of are.

The spindle, 14, has fixed thereupon four elongated soft iron members or elements, 2C, 3, 4, and 5, of thin sheet, one at the center of each set of coils. Each successively lower placed element is displaced 90, counter-clockwise, with reference to the element immediately above it.

The rotating system consisting, as it does, of only the spindle proper, 14, the four small and thin soft iron elements, 2C, 3C, 4C, and 5C, the quadrantal segment, the worm, 25, and the aluminum cup, 24. is e2;- ceedingly light, thus making it possible to have correspondingly small frictional losses in the bearings.

The load coils, 6, of each set of coils, 2, 3, 4, and 5, have their terminals preferably in The E. M; F. coils of the top and third sets, c' e., oit sets 2, and, 4, have their corresponding terminals joined respectiveljr to conductors 43, 44, which go to opposite leaf springs, 2", and 4. Similarly, the E. M. F. coils oi sets, 3, and, 5, are joined respectively to opposite leal springs, 3b, and 5".

All the outer contacts, 30, are connected together and to a terminal binding post,

45; and all the inner contacts, 31, are joinedk together and to a terminal binding post, 46.

The description just above given will be aided by reference to Fig. 3 where all the operative connections and parts are shown schematically, including the manner of connecting the meter tothe circuit whose energy consumption is to be measured.

As shown in this figure the terminal posts, 41, and, 42, are joined to the ends of a load shunt, 47, inserted in one of the main supply wires, 48, 49, between the generator and the load. The magnitude of the load shunt is, of course, determined with relation to the ampere turns of the load and E. M. F. coils as well as with respect to other usual considerations, well understood by those skilled in the art, so as to provide a suitable voltage drop at the terminals of the load coils.

Binding posts, 45, and 4.6, are respectively joined by conductors 50, 51, one of which includes a resistance, 52, to the two main supply wires, 48, 49.

The entire meter is inclosed in a casing of soit iron comprising a tubular section 53, and top and bottom caps 54 and 55.

The operation of the meter is as` follows: Assuming that the main circuit is carrying a load, the four load coils, 6, of sets, 2, 3, 4,

and, 5, will all be similarly and continuously energized so as to develop an equal and similarly directed magnetic-flux. Let us suppose this direction to be upwardly and let us call this a positive or a -I- iiux, a`

downwardly directed flux being, conversely, called a negative or a flux. For convenience, we will assume that when the upper blocks, 35, and, 38, of the load and E. M. F. coils, respectively, are the magnetic iiux of such coils will also be -lwhile, if these blocks are the magnetic-flux will be correspondingly v Considering the E. M. F. coils, 7, 1t will be noted that the leaf springs, 2b, and, 4b, to which the terminals or' the E. M. F. coils of sets, 2, and, 4, are joined, are both resting against their outer contacts, 30. These voltage coils (i. e., of sets 2 and 4) are thus both short-circuited and developing, of course, no magnetic-flux.

Owing to the fact, however, that the ro,- tating system, 13, has brought the magnetic segment, 34, immediately adjacent to leaf spring, 3b, this particularV spring will be pulled inwardly against the inner contact, 31, of the contact pair, Sn. This will cause the voltage coils of sets, 3, and, 5, to be joined in parallel, but oppositely, between the terminal posts, 45, and, 46, so as to develop an equal but opposite magnetic-flux. y

The direction of this fiux in the voltage coil f spindle, 14, that, with the rotating system as shown in Figs. 1 to 3, members, 3C, and, 5C, will be subjected to maximum torque by any magnetic fluxV developed in their corresponding load and voltage coils, while members, 2C, and, 4, will be subjected to minimum torque.

The torques acting upon members, 3, and, 5c, or upon members, 2C, and, 4C, will, however, be opposite in direction and proportional to the magnitude of the magneticiiux irrespective of its directions, c'. e., without regard to whether this flux is positive orA negative.

Considering the load coils only, all of which are developing equal and similarly directed magnetic fluxes, their net elfect upon the 'rotating system will be m'Z since the torque exerted upon members, 3C, and 50, will be equal and opposite and, similarly, the torque exerted upon members, 2C, and, 4C, will be equal and opposite.

Similarly, considering only the E. M. F.

coils, the torques exerted upon members, 35,..

and 5C, willbe equal and opposite as will also be the torques exerted upon the members, 2, and, 4c. n

The above condition of stable equilibrium will obviously be true for any and every position of the rotating system ir" either the effect of the load coils or of the E. M. F. coils, taken alone, be considered.

Let f1 be the flux developed by each load coil and f" be the flux developed by each voltage or E. M. F. coil. Then, with conditions as shown in Figs. 1 to 3 and above described, the total fiux due to the load and E. M. F. coils of set, 3, will be )W4-f1 since both fluxes are `With respect to the coils of set, 5, however, the total fiux will be fl-f since the load fluxes are here opposite, that of the E. M. F, coil being The not torque exerted upon the rotating system, thcrenc, may be expressed as.

Misurar-(zr-rr] rziitflfv and the ro ta ting system will be turned countor-clockwise.

rlhe magnetic segment, 34, will now be brought adjacent to the leaf spring, 4b, which will, in its turn, be drawn inwardly against the inner contact, 31, of Contact pair, 4, thus causing the EQM. F. coils ot' sets, 2, and, to be energized, the former so as to develop a-iiux, and the latter a-l flux. Similarly, but a little ai'ter the ieai2 spring, 4, has been drawn inwardly, lear" spring, 3b, will be released so as to again short-circuit the E. M. F. coils or' sets, 3, and, 5, and render these sets torqueless as regards the rotating system.

Coil set, 4, will now develop a flux, f1, due to its load coil and a -lflux, fv, due to its E. M. F. coil while coil set, 2, will develop a -llux j, due to the load coil and a flux, 7'", due to the E. M. F. coil. The

net torque due to coil sets, 2, and, 4, will,

and also as before, its direction will be such as to turn the rotating system counter-clockwise.

Magnetic segment, 34, will now be carried djacent to leat spring, 5', so as to draw it against the inner Contact, 31, of contact pair 51. This will cause the E. M. F. coils of set-s, 3, and, 5, to be again energized but this time reversely as compared with their conditionL when last energized (i. e., when magnetic segment, 34, was diametrally opposite its now position). rlie E. M. F. coil of set, 5, will now have a -liiux, 'v, and the E. M. F. coil of set 3 will have a iiux, fv...

Again the net torque may be expressed as and again the direction ot rotation will be counterecloolwise.

llfiagnetic segment, 34, will now be brought adjacent to leaf spring, 2b, so as to draw it against the inner contact, 31, of contact pair, 2, lThis will cause the M. F. coils of sets, 2, and, 4, to be again energized by this time reversely as compared with their condition when last energized e., when magnetic segment, 34, was diametrally opposite its present position). The E. M. F. coil set, 2, will now have a -lflux, f, and the E. M. F. coil set, 4, will have a iiux, fv.

The net torque will be, as before,

and the direction of rotation will, as before, be counter-clockwise.

This completes a working cycle, the rotating system having been turned through 360O and the parts thereof being again in the same position with reference to the coil sets and other positions of the meter as obtained at the beginning of the cycle.

The various constants of the several sets of coils should be so determined that the magnitude of the flux due to the E. M. F. coils, this flux value being obviously substantially constant, will always be greater than that due to the load coils even at the maximum load. The direction of the iiux due to each and every set or pair of coils (2'. e., the E. M. F. coil and its associated load coil) will always be the same as that ot its E. M. F. coil.

It will be noted that coil sets, 2, and, 4, conjointly exert maximum torque upon the rotating system each time the system passes through points 180O apart, the torque, due to coils, 3, and, 5, being then zero. Similarly, coil sets, 3, and, 5, exertA maximum torque and coil sets, 2, and, 4, zero torque at points 180o apart but midway between points lirst referred to. The rotating system is thus subjected to maximum torque at each 900 of its rotation, this torque being alternately due first to one pair of coil sets, 2, and, 4, and then to the other pair of coil sets, 3, and, 5.

1t will also be noted that the direction of the joint flux developed by each and every coil set will be reversed, i. e., alternately positive and negative, for every 180o rotation ot' the rotating system.

1t will also be clear that the action of coil sets, 2, and 4, is quite independent of the action of coil sets, 3', and, 5, and that, in principle, but one pair of these coil sets is essential; the remaining set being used merely to approximate the condition of a continuously applied torque. Hence, I may, if I desire, employ a greater number of pairs of coil sets, three, e. g., arranging them to act successively at intervals of 600; or four sets, arranging them to act successively at intervals of 450. The soft iron elements, 2C, 3C, etc., would, of course, have to be increased in correspondence with the increased number of pairs of coil sets and their angles or relative displacement corre` spondingly altered. The number of contact pairs, 2?, 3a, etc., and their angles of relative displacement would, of course, also require to be suitably changed.

Any increase in the number of pairs of coil sets employed, however, will increase the size of the meter, the cost of manufacture, and in general, will make the meter more complex.

It will also entail an added weight for the rotating system and hence increase the frictional loss.

Owing to the reversal in direction of the magnetic flux due to each coil set for each 1800 rotation of the rotating system, it follows that the several soft iron elements 2c, 3C, etc., are correspondingly alternately reversed in magnetism, e'. e., are passed through the hysteretic loop. The meter, therefore, is free from hysteresis errors.

The casing, 53, 54, and, 55, is exceedingly simple and cheap to make, ordinary soft iron pipe `being suitable therefor; it will electually protect the operative parts of the meter from stray magnetic fields and, hence, *against errors consequent thereupon.

I have illustrated and described a preferred form of my invention. However, many details may be changed within the spirit thereof and within the scope of the claims which will hereafter-follow.

Thus, it is not essential that the coil sets and the soft iron elements 2, 3C, etc., should bev inclined at 450 as shown. They need not, indeed, be inclined at all, provided merely that they be relatively arranged so that the coil sets are able to exert torque upon the rotating system by their paired action upon the Vseveral soft iron elements, hence the planes of the coil sets may be vertical or horizontal or inclined at any desired angle thereto, the soft iron elementsY being suitably disposed in correspondence therewith.

Similarly, the magnetic commutating switch, while possessing many advantagesand being, according to my present view, a preferred arrangement, is not essential, and other commutating devices may be employed within the spirit of the invention and without any substantial change withy respect to other features of construction which have been mentioned.

Having described my invention, I claim: l. In an electric meter of the class described, a rotatable system having a soft iron element fixed thereto, two identical pairs of stationary coils similarly disposed as to the axis of rotation of the aforesaid system and adapted to exert opposite torques upon the iron element, each pair having an E. M. F. coil and a load coil, the load coils being adapted to carry certain currents such that the current iow is proportional to the load and the E. M. F. coils being adapted to carry certain currents such that the current How is proportional to the E. M. F., the current flow in one pair of coils being in the same direction and in the other pair of coils being in opposite directions, and

means for simultaneously reversing the E. M. F. coils in synchronism with the r0- tation of the soft iron element.

2. In an electric meter of the class described, a rotatable system having a soft iron element fixed thereto, two identical pairs of stationary coils similarly disposed as to the axis of rotation of the aforesaid system and adapted to exert opposite torques upon the iron element, each pair having an E. M. F. coil and a load coil, the load coils being adapted to carry certain currents such that the current flow is proportional to the load and the E. M. F. coils being adapted to carry certain currents such that the current flow is proportional to the E. M. F., the current flow in one pair of coils being in the same' direction and in the other pair of coils being in opposite directions, and a commutator controlled by the rotation of' the rotatable system for simultaneously reversing the E. M. F. coils -in synchronism therewith. 1

3. In an electric meter of the class described, a rotatable system having a soft iron element fixed thereto, two identical pairs of stationary coils similarly disposed as to the axis of rotation of the aforesaid Asystem and adapted to exert opposite torques upon the iron element, each pair having an E. M. F. coil and a load coil, the load coils being adapted to carry certain currents such that the current flow is proportional to the f load and the E. M. F. coils carrying current 

